Endoluminal exclusion of abdominal aortic aneurysms (AAA) by transluminal implantation of stent grafts has in selected cases become an attractive alternative to open surgical aneurysmal repair. It has been done on an elective basis after detailed preoperative visualization and measurements are made of the aneurysmal and adjacent arterial anatomy. Recent developments and a greater variety of new stent graft systems has enabled endoluminal exclusion to be extended to patients with ruptured AAA and to perform it on emergency basis. The stent graft systems for both elective and emergency AAA exclusions have been constructed with conventional surgical synthetic materials DACRON® or polytetrafluoroethylene (PTFE) supported by metallic expandable stents.
Conventionally, stent grafts that are emplaced within the vascular networks include one or more stents affixed to graft material. The stent grafts are secured at a treatment site by endovascular insertion utilizing introducers and catheters, whereafter they are enlarged radially and remain in place by self-attachment to the vessel wall. In particular, stent grafts are known for use in treating descending thoracic and abdominal aortic aneurysms where the stent graft at one end defines a single lumen for placement within the aorta and at the other end is bifurcated to define two lumens, for extending into the branch arteries.
One example of such a stent graft is disclosed in PCT Publication No. WO 98/53761 in which the stent graft includes a sleeve or tube of biocompatible graft material (such as DACRON® or polytetrafluoroethylene) defining a lumen, and further includes several stents secured therealong, with the stent graft spanning the aneurysm extending along the aorta proximally from the two iliac arteries; the reference also discloses the manner of deploying the stent graft in the patient utilizing an introducer assembly. The graft material-covered portion of the single-lumen proximal end of the stent graft bears against the wall of the aorta above the aneurysm to seal the aneurysm at a location that is spaced distally of (farther from the heart) the entrances to the renal arteries. Thin wire struts of a proximal stent extension traverse the renal artery entrances without occluding them, since no graft material is utilized along the proximal stent while securing the stent graft in position within the aorta when the stent self-expands. An extension is affixed to one of the legs of the stent graft to extend along a respective iliac artery and, optionally, extensions may be affixed to both legs. Another known stent graft is the ZENITH™ AAA stent graft sold by William A. Cook Pty. Ltd., Brisbane, Queensland, AU.